The present invention relates to a vehicular headlamp assembly provided with a measuring device for checking the aiming directions of right and left light beams of the headlamp to determine whether or not the angle between the right and left light beams is properly set. More particularly, the invention relates to a vehicular headlamp assembly which can easily adjust the angle between the right and left light beams, when not properly set, to the correct angle.
A headlamp apparatus of the tiltable reflector type in which a reflector is tiltably supported in a headlamp body will be described as an example of a vehicular headlamp assembly to which the invention can be applied. As shown in FIG. 1, a reflector b is mounted on its rear surface to a lamp body a by means of two aiming screws c and d, which extend in the front-to-rear direction of the headlamp, and a pivot e. In FIG. 1, in which the reflector is seen from the front side, the aiming screws c and d extend vertically with respect to the plane of the drawing.
The aiming screws c and d are rotatably supported on the rear side of the lamp body a. The support points of the reflector b supported by the aiming screws c and d are orthogonal to the pivot e as seen from the front of the headlamp. The reflector b can be tilted about a horizontal axis L.sub.x and a vertical axis L.sub.y by turning the aiming screws c and d, whereby the angle between the two light beams is adjusted. Reference character f designates a bulb as a light source mounted on the reflector b.
There is known another headlamp apparatus of the tiltable unit type in which a lamp body reflector unit is tiltable about a lamp housing. The lamp body reflector unit is constructed such that the reflector is integral with the spherical inner surface of the lamp body. The tiltable unit headlamp apparatus, like the tiltable reflector headlamp apparatus, is constructed such that the lamp body reflector unit is supported on the lamp housing by means of one pivot and two aiming screws. The light beam angle of the headlamp is adjusted by adjusting the tilt angle of the reflector unit. In this case, the reflector unit is tilted by turning the aiming screws.
As described above, in the conventional vehicular headlamp apparatuses, the light beam angle of the headlamp is adjusted in a such a manner that the tilting member (the reflector in the tiltable reflector headlamp apparatus and the lamp-body/reflector unit in the tiltable unit headlamp apparatus), the orientation of the reflecting surface of which determines the light beam direction, is tilted horizontally (about the vertical axis) and vertically (about the horizontal axis) with respect to the reference member (the lamp body in the tiltable reflector headlamp apparatus and the lamp housing in the tiltable unit headlamp apparatus).
Many proposals have been made for the measuring device for measuring the horizonal light beam angle of the headlamp in a simple manner. U.S. Pat. Nos. 5,138,532, 5,121,303, and 5,029,051, all commonly assigned herewith, disclose several examples.
In all of those proposals, the measuring device for measuring the horizontal tilt of the tilting member is installed between the tilting member and the reference member. Further, it is frequently placed at a location above the lamp for ease of reading the scale. This results in increasing the height of the headlamp. The increased height is contradictory to the recent market trend for flat-type headlamps. Particularly, in the tiltable reflector headlamp apparatus, the measuring device is located within the lamp body. This construction makes it difficult to read the scale.
A tilt measuring device, such as disclosed in U.S. Pat. No. 5,121,303, is illustrated in FIG. 2. As shown therein, a transparent case g protrudes from the rear side of a lamp body a. The first half of a sliding bar h is slidably located in the transparent case g. The second half thereof extends through the lamp body a and resiliently contacts the rear side (side bracket) of the reflector b. A relative scale is provided between the rear end h1 of the sliding bar h and the transparent case g. The amount of the horizontal tilt of the reflector b is measured on the basis of the displacement of the sliding bar h relative to the transparent case g. Reference symbol i designates a compression coiled spring.
In the measuring device structure of FIG. 2, a hole through which the sliding bar h passes must be formed in the lamp body a as the reference member. The work to form the hole in the lamp body is troublesome in production. Further, careful adjustment is required when the measuring device is assembled into the lamp body.
A tilt measuring device previously proposed by the present applicant is shown in FIG. 3. As shown, a guide member 101 protrudes from the rear side of a lamp body a. A slide case 102, coupled with the guide member 101, is slidable in the direction of the guide member extension. A nut 103, which receives a horizontal aiming screw c, is slidable within the slide case 102. A zero-adjustment screw 104 is interposed between the nut 103 and the slide case 102.
In operation, an indicator 106 between the guide member 101 and the slide case 102 is preset to indicate a zero point 105a on the scale 105. When the reflector tilts in the horizontal direction, the indicator 106 moves to indicate the amount of tilt of the reflector. The indicator 106 is adjusted to point to the zero point 105a by turning the zero-adjustment screw 104. As seen, in this technique, the measuring device for measuring the horizontal tilt of the light beam angle of the headlamp is assembled into the section protruding from the lamp body a. Accordingly, there is no need of the troublesome work to form a hole for the measuring device. Further, the height of the headlamp can be reduced.
In the case of the measuring device of FIG. 3, the guide member 101, which is shaped like a bar and has a scale formed thereon, is thin. Accordingly, when the headlamp is mounted on the car body or the aiming or zero adjustment is carried out, if a worker mistakenly hits the guide member with a tool such as a driver or wrench, the guide member can be easily damaged or broken.
Additionally, the conventional measuring devices require a great number of parts and a complicated construction. Accordingly, the cost of manufacture is high and the assembly work of the measuring device to the headlamp is complicated.